1. Field of the Invention
The present invention relates to a computer system, and deals more particularly with a method, system, computer program product, and method of doing business by digitally notarizing a collection of data streams.
2. Description of the Related Art
Pervasive devices, sometimes referred to as pervasive computing devices, are becoming increasingly popular, and their functionality (in terms of communication and processing capabilities) is increasing rapidly as well. Pervasive devices are often quite different from the devices an end-user might use in an office setting, such as a desktop computer. Typically, a pervasive device is small, lightweight, and may have a relatively limited amount of storage. Example devices include: pagers; cellular phones, which may optionally be enabled for communicating with the Internet or World Wide Web (“Web”); foreign language translation devices; electronic address book devices; wearable computing devices; devices mounted in a vehicle, such as an on-board navigation system; computing devices adapted to use in the home, such as an intelligent sensor built into a kitchen appliance; mobile computers; personal digital assistants, or “PDAs”; handheld computers such as the PalmPilot™ from 3Com Corporation and the WorkPad® from the International Business Machines Corporations (“IBM”); etc. (“PalmPilot” is a trademark of 3Com Corporation, and “Workpad” is a registered trademark of IBM.)
Pervasive computing to date has focused on providing unique “point-solution” devices (i.e. single-purpose devices) to address specific and limited functionality needs. The consolidation of multiple categories of functionality into integrated devices has started, but is not very far along yet. This type of functional convergence into an integrated, multi-function package is attractive because it reduces the number of devices a consumer must buy and maintain, and can be expected to reduce the consumer's financial outlay in the process. However, functional convergence poses a dilemma for manufacturers, who have to try to guess which combinations will be attractive to consumers and deliver this integrated function at a competitive price-point. If the manufacturer guesses incorrectly when choosing functionality to combine, it may be left with an unwanted product and millions of dollars in wasted expenditures. Some industry experts believe that consumer preferences will vary even among geographical regions. (See “Vendors Race to Put Cameras in Cell Phones”, J. Yoshida, EE Times (Sep. 11, 2000), which discusses product requirements for adding digital camera still imaging and video imaging capability to cell phones.) Functional convergence also poses a dilemma for consumers, who have to decide which pervasive devices, with which combinations of functions, to acquire and incorporate into their mobile life-style.
An additional drawback of functionally convergent devices is that, in most cases, security functions have been added to these devices as an afterthought, only after expensive security breaches were detected. For example, strong digital authentication was added to analog cell phones only after hackers were found to have stolen long distance service by cloning phone identities, and digital audio players were made more secure only after the discovery of widespread theft of licensed intellectual property (i.e. music recordings).
Let us review the state of the prior art in the field of pervasive computing, as represented by a mobile professional equipped with a collection of the latest generation of specialized personal devices. She may have a cellular telephone, a two-way pager, a “smart” credit card (also known as a “smart card”), a “smart” employee badge used to access secure areas, a PDA, a digital still camera, a digital video camera, a dictation recorder with voice recognition capability, an MP3 music player, a remote control key-chain for access to an automobile, a second remote control key-chain for access to a garage, a global positioning system (GPS) navigation aid and map pad, a weather-alert radio, and a personal health alert fob to summon medical aid—all of which may be capable of interacting wirelessly with one another, perhaps via short-range radio technology such as Bluetooth. (“Bluetooth” is a standardized technology that enables devices containing a low-powered radio module to be automatically detected upon coming into radio proximity with one or more other similarly-equipped devices. Devices incorporating this technique are referred to as “Bluetooth-enabled” devices. A standard defining the Bluetooth techniques may be found on the Web at http://www.bluetooth.com.)
One problem is that this array of devices is simply too large! It is unlikely that a person will carry all of these on every outing or trip. Even if she did, will she remember to charge each device's batteries?
A second shortcoming is that prior-art devices are designed to operate independently—i.e. not to rely on other devices for operation. This implies significant functional duplication across devices.
There has recently been a focus on interconnecting the initial generation of point-solution pervasive devices such as those in the example into loosely-coupled personal networks via wireless (e.g. radio or infrared) technology. However, this type of interconnection creates additional security exposures. For example, a hacker may eavesdrop on the wireless transmissions between devices and maliciously use data that has been intercepted. Even though such ad-hoc collections of networked personal devices offer the potential for exploiting the devices in new ways and creating new methods of doing business, these new avenues cannot be fully exploited until security issues are addressed.
A collection of prior-art devices is generally unsecure unless each device contains a secure component capable of recognizing the authenticity of its neighbors, of the user, and of the application software it contains. This means that a loosely coupled “secure” solution built from prior art devices has numerous costly duplicate security components, both hardware (for example, protected key storage, buttons or other human-usable input means, display means, and so forth) and software. Additionally, a loosely coupled collection of prior-art devices has poor usability because of the need for multiple sign-ons to establish user identity, and the need to administer lists defining trust relationships among devices that may potentially communicate. The result in the real world is an unsecure solution. This is because only rudimentary security is implemented in an individual device, due to cost, and every communication pathway (especially wireless ones) between devices is subject to attack. These problems rule out the practical implementation of many useful functions and high-level business methods using collections of prior-art devices.
Consider, for example, a method of doing business wherein a consumer orders merchandise on the Web using a communicating collection of three specialized prior art devices. The devices are: (1) a smart credit card, (2) a PDA with a Web browser, and (3) a cellular telephone which acts as a modem for connecting the browser to a Web server application. Assume for purposes of discussion that the three devices communicate locally using wireless technology such as Bluetooth radio.
Once the user has finished selecting merchandise, he needs to sign the order with his credit card's credentials. To do this, the smart credit card first needs to verify the user's identity. Prior art smart cards have neither a display to query the user for identity information, nor a button or other indicator with which the user can indicate his approval of a trust relationship. Typically, the user would prove his identity to the smart card by keying in a secret input (such as a personal identification number, or “PIN”) on a keyboard of the PDA, where the smart card has previously been mechanically coupled to a smart-card reader which is also operably attached to the PDA. The user's input is then transmitted via the mechanical link to the smart card for verification.
The first problem in this scenario is that application code is executing in the same device to which the input sensor is connected. Today there is little to prevent a hacker from installing a Trojan horse-style virus (or other malicious application code) in a PDA. Such a virus could eavesdrop on the user's secret information, intercept this information, and then report it back to a server application; it could record a transaction signed by the user's smart card for later playback without the user's authorization; or it could trick a user into signing a transaction that contains modified data. (Recently the first virus infestations of cell phones were reported, and it can be expected that such attacks will surface more frequently with personal computing and personal communication devices as increasingly valuable amounts of e-business are transacted wirelessly.) While a challenge/response sequence in the Web shopping application could avoid the playback problem, it means an extremely inconvenient human interface (which may comprise a game of 20 questions, e.g., “What is your mother's maiden name, your home phone number, your zip code, your birth date, the last four digits of your social security number, your place of birth, your pet's name?”, etc.). Not only is this inconvenient, but it provides another opportunity for security to be compromised: once a user divulges her personal answers to these questions to one Web merchant, the answers could be used by an unscrupulous person to gain unauthorized access to some other Web site that uses the same questions for authorization.
Suppose that the user's identity has been successfully verified. After this occurs, the order must be signed. This comprises transmitting the unsigned order to the smart credit card, which signs it using the user's private key and returns it, digitally signed and legally binding upon the user, to the PDA's browser for transmission to a merchant. But another security exposure arises in the signing process, in that it is not possible using these prior art techniques to know that what was displayed to the user equalled what was sent to the card for signature. For example, the display presented to the user may perhaps show an order for a dozen grapefruit, while in fact a server may have been hacked to install a trojan JavaScript to execute on the PDA that would trick the user into signing an order for a dozen diamond rings by modifying the transaction before sending it to the smart card for signature. Digitally signed transactions are intended to be legally binding and not subject to repudiation by the user, and thus it is imperative that appropriate security measures are in place to ensure that the user's digitally signed data represents the transaction to which the user actually assented.
U.S. Pat. No. 6,772,331, entitled “Method and Apparatus for Exclusively Pairing Wireless Devices”, (Ser. No. 09/316,686, filed May 21, 1999) taught a technique for establishing secure trusted relationships between devices in a Bluetooth network using special-purpose hardware, along with software on each device. The special-purpose hardware comprises, for example, a protected memory for storing a digital signature, where this memory is physically attached to the radio transmitter of each device; a display screen on at least one device capable of showing a media access control (MAC) address of the device; and an input button or other comparable device on at least one device for the user to indicate his assent to a trust relationship. While the disclosed technique provides security improvements for networking a collection of devices, there is a significant cost involved. Even if such an investment were made, the overall business process would remain unsecure against certain types of attacks. Furthermore, the disclosed technique cannot be applied to prior art smart credit cards, which have neither a display nor a button for indicating trust.
Accordingly, what is needed is a technique whereby multiple functions can be conveniently and economically provided in a single personal device, while still ensuring the security of the device and the operations it performs.